1. Field of the Invention
In general, the present invention relates to dental prosthetic devices such as crowns and bridges that attach to the fixture of a dental implant. More particularly, the present invention relates to the method of forming dental prosthetic devices and the method of anchoring such prosthetic devices to the fixture of a dental implant.
2. Description of the Prior Art
In dentistry, the use of dental implants is becoming increasingly popular as a means of anchoring prosthetic devices within the mouth. By using dental implants, prosthetic devices can be anchored directly to bone, as opposed to being anchored to other teeth within the mouth. Accordingly, the stability of the prosthesis does not rely upon the condition of the other teeth within the mouth. Similarly, should the condition of other teeth in the mouth degrade over time, the stability of the prosthesis will remain unaffected.
Dental implants typically include metal fixtures that are surgically inserted into either the bone of the maxillary arch or the bone of the mandibular arch. As the bone grows around the base of the fixture, the fixture becomes firmly set into the bone.
After a fixture has set into the bone and the fixture has healed, an abutment is commonly attached to the fixture. In the prior art, the abutment is a metal structure that is shaped to receive a prosthetic device. The prosthetic device is usually a crown or a bridge that is fabricated using traditional impression modelling techniques. Traditionally, prosthetic devices used in conjunction with dental implants have a metal core upon which porcelain or another laminate structure is applied. The metal core of the prosthetic device is shaped to receive the abutment segment of the implant. As such, a metal-to-metal mechanical interconnection is created between the abutment and the prosthetic device. Such prior art devices and methods are exemplified in U.S. Pat. No. 5,556,280 to Pelak, entitled Method And Apparatus For Appliance Mounting.
Metal-to-metal interconnections between implant abutments and dental prosthetic devices produce very stable and reliable anchoring connections for the prosthetic devices. However, the use of metal does have its disadvantages. If a metal core is used within a prosthetic device, that prosthetic device is opaque. Natural teeth are partially translucent. Accordingly, a prosthetic device with a metal core will never truly have the same appearance as a natural tooth, regardless of its color. Furthermore, in some patients, there can be bio-incompatibility issues when metal is introduced into the mouth. The incompatibility can prevent proper growth of the gums around the base of the prosthetic device.
Recognizing the disadvantages of metal core dental prosthetics, many systems and methods have been developed in the prior art for forming prosthetic dental devices that do not contain metal. Such systems typically utilize fiber reinforced composite materials. In such prior art systems, the fiber reinforced material must be anchored between adjacent teeth because the fiber reinforced material does not bond well to the metal of a dental implant. Furthermore, significant portions of the adjacent teeth must be removed in order to form the structure required to engage the fiber reinforced composite material. Accordingly, the strength of any prosthesis that utilizes fiber reinforced composite material is dependent upon the strength, size and condition of the teeth adjacent to the prosthesis. Furthermore, if any occlusion between teeth is greater than just one or two teeth, such prior art systems cannot be used due to the lack of support available. Prior art systems that utilize fiber reinforced composite material are exemplified by U.S. Pat. No. 4,867,683 to Meisel, entitled Anchoring Device For Dental Prosthesis; U.S. Pat. No. 4,894,012 to Goldberg, entitled Passive Dental Appliances Of Fiber-Reinforced Composites; and U.S. Pat. No. 5,171,147 to Burgess, entitled Dental Bridge.
A need therefore exists for a system and method of forming a metal free prosthetic device that can be attached to the fixture of a dental implant, thereby producing an aesthetically pleasing prosthesis that is anchored directly to bone. This need is met by the present invention system and method as described and claimed below.